Google made an announcement of a limited test of App Script at the same time that Google Wave was announced. Wave gained much of the attention but App Script has the potential to be far more important. Initially App Script is just available in Google Docs spreadsheets for a limited number of users, but this will expand over time.

So what is it?

Well App Script allows you to write functions in Javascript that run directly on Google's servers. Just to repeat the code runs on Google servers not in the browser. This really is the next step in the 'programmable web'. So now instead of having to write a full Google App Engine application or set up Amazon EC2 instances with a full server environment you can just write a Javascript function and have it running on Googles servers. (Yahoo are also providing a service where you write Javascript that executes on their servers - YQL Execute)

This will allow mash-ups on the server side, whereas currently mash-ups have resided within the browser. As more web services allow server-side scripting the web really will turn into a fully scriptable environment. Previously applications that would have required complete custom development will just require integrating together of sevices with scripting to provided the desired application.

With Javascript becoming the universal language and JSON providing the standard for data transfer along with oAuth for security - all of the pieces are falling into place to provide a complete distributed development environment hosted within the cloud and based on the cloud, rather than the old model of a single development environment by a single supplier.

The potential for this cannot be overestimated, Google Wave is fantastic but with App Scripting it will be just a messaging service that is tied into cloud hosted applications using many other services.

I grew a software business in the UK and then managed it's acquisition by a US company. Now I'm building a new start-up and providing short term consultancy for software projects and software business process, if you need help with your project get in contact.When the internets are off entertaining a 7 year old occupies quite a bit of the time.